Both on my local up to date installations and on https://secure.phabricator.com/maniphest/report/project/:

Unhandled Exception ("PhabricatorDataNotAttachedException")

Attempting to access attached data on ManiphestTask (via getProjectPHIDs()), but the data is not actually attached. Before accessing attachable data on an object, you must load and attach it. Data is normally attached by calling the corresponding needX() method on the Query class when the object is loaded. You can also call the corresponding attachX() method explicitly.